[PATCH -next v2] usb: add usb.h stubs for CONFIG_USB not enabled

From: Randy Dunlap
Date: Sat May 19 2012 - 12:31:05 EST


From: Randy Dunlap <rdunlap@xxxxxxxxxxxx>

Add stubs for some usb core functions when CONFIG_USB
is not enabled. This fixes these comedi build errors:

ERROR: "usb_deregister" [drivers/staging/comedi/comedi.ko] undefined!
ERROR: "usb_register_driver" [drivers/staging/comedi/comedi.ko] undefined!

Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxx>
---
I am only adding the stubs that are needed for comedi to build.
I expect that more stubs will be needed as more build errors are
found. It seems to me that linux/usb.h might need more (major)
moving of lines to support more stubs in the future.

Documentation/usb/error-codes.txt | 2 ++
include/linux/usb.h | 25 ++++++++++++++++++++++++-
2 files changed, 26 insertions(+), 1 deletion(-)

--- linux-next-20120518.orig/include/linux/usb.h
+++ linux-next-20120518/include/linux/usb.h
@@ -10,10 +10,11 @@

#ifdef __KERNEL__

-#include <linux/errno.h> /* for -ENODEV */
+#include <linux/errno.h> /* for -ENODEV, -ENOSYS */
#include <linux/delay.h> /* for mdelay() */
#include <linux/interrupt.h> /* for in_interrupt() */
#include <linux/list.h> /* for struct list_head */
+#include <linux/kconfig.h> /* for IS_ENABLED() */
#include <linux/kref.h> /* for struct kref */
#include <linux/device.h> /* for struct device */
#include <linux/fs.h> /* for struct file_operations */
@@ -515,6 +516,8 @@ static inline struct usb_device *interfa
return to_usb_device(intf->dev.parent);
}

+#if IS_ENABLED(CONFIG_USB)
+
extern struct usb_device *usb_get_dev(struct usb_device *dev);
extern void usb_put_dev(struct usb_device *dev);

@@ -976,6 +979,26 @@ extern void usb_deregister_dev(struct us

extern int usb_disabled(void);

+#else /* stubs for USB not enabled */
+
+static inline int usb_register(struct usb_driver *driver)
+{
+ return -ENOSYS;
+}
+
+static inline int usb_register_driver(struct usb_driver *driver,
+ struct module *mod,
+ const char *modname)
+{
+ return -ENOSYS;
+}
+
+static inline void usb_deregister(struct usb_driver *driver)
+{
+}
+
+#endif
+
/* ----------------------------------------------------------------------- */

/*
--- linux-next-20120518.orig/Documentation/usb/error-codes.txt
+++ linux-next-20120518/Documentation/usb/error-codes.txt
@@ -167,6 +167,8 @@ processing, devices may receive such fau

usb_register():
-EINVAL error during registering new driver
+-ENOSYS CONFIG_USB is not enabled, so the function stub
+ returns an error.

usb_get_*/usb_set_*():
usb_control_msg():
--
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